Apparatus for forming closed tubes



#11.26, .1943. @E FRANCK- 2,309,181-

APPARATUS FOR FORHING CLOSERTUBES Filed Nov. 12, 1940 Patented Jan. 26,i943 UNITED STATES IPATENT OFFICE APPARATUS FOR FORMING CLOSED TUBESGeorge E. Franck, Riverside, Ill., assigner to The Imperial BrassManufacturing Company, Chicago, Ill., a corporation oi' Illinois Claims.

made of metal' and formed from a single length of stock into tubessubstantially closed at both ends andv suitablel forming apparatussuchas dies and appurtenances thereto for forming such containers.

Among the objects of my invention is to provide a new and improvedapparatus for forming a substantially cylindrical container havingsubstantially closed ends by operation upon a length of metalliccylindrical tubing stock.

A further object is to provide an apparatus consisting of dies and acentering means cooperable with the dies which are adapted to receive apiece of tubular stoel: centered properly within the dies and thencompress the stock at one or at both ends simultaneously into the closedform of container desired and then open so that the container thusformed might be removed without it being necessary to break apart anyparts of the separate coacting die platens.

It is further among the objects to provide platens and centeringmechanism therewith which is adapted ilo/ correct 'en stock of apredetermined' sizeffwhie' slightly over or under size or "whic maaddition have irregularities on the surface.'

With these and other objects in view, my invention consists in theconstruction, arrangement and combination of the various steps of mymethod together with parts of my device whereby the objects contemplatedare attained, as hereinai-ter more fully set forth, pointed out in myclaims and illustrated in the accompanying drawing, in which:

Figure 1 is an elevational view in section showing upper and lower dieplatens and a length ci stock in place prior to the forming operation.

Figure 2 is a vertical sectional view similar to Figure l, showing thedie platens in compressed position. v

Figure 3 is a cross-sectional view taken on the line 3--1 o! Figure 1.

l Figure 4 shows a method of heat treating the end oi' the tubular stockwhich is to be formed.

It has previously been the custom to use tubular stock for devices suchas filters, dehydrators, strainers, scale traps, etc., which are citenused in liquid and gas lines where the liquid or gas is underconsiderable pressure or which may be of such-a nature as to enable itto leak out wherever even a'very slight leak might occur. YIt haslikewise been the practice when making either by provi/ding threadedcaps or when especially high pressures are encountered by attachf y lngtheretovanges which are bolted together.

Such constructions are relativeLv expensive and entail a large number ofmanufacturing operations. Moreover, even when so designed, the

capped and threaded stock is unsuitable for very high pressures.

Metallic bodies having curved closed ends have frequently been found inthe past to have great strength in proportion `to the gauge of the metalformed into such rounded shapes. However, in

providing a method for forming tubes ot relatively small diameter intosuch shapes having,v

rounded ends a dlfllcult problem is presented since all of the work mustbe perfumed upon the stock from the outside and no backing o rsupporting structure can be effectively positioned within the Itubewhile the forming operation takes place.

This method and the apparatus, therefore, is directed to the provisionof a means whereby tube v4'stock of relatively small diameter'may be'outl and formed into containers comprising a single piece havingrounded ends and which by reason of such construction have relativelygreat ystrength in proportion tothe gauge of the metal forming thetubular stock.

One embodiment of my invention directed to the provision of such anapparatus for prac. ticing my method is shown on the drawing;

where an upper platen I0 is shown opposed to a lower platen |2'whereineach are provided with suitable recesses for positioning and compressinga length of tubular stock I 4, as shown in Figure l, into a desired formI6, shown in Figure 2.

The upper platen l0 has'a recess comprising an annular curved portion'.I8 and a. cylindrical portion 20. The cylindrical portion has a diametersubstantially equal to the outer diameter of the tube stock 'il so thatthe stock may slide easily into the recess. At the center of .the recessis a plug 22 having a conical end 24 extending into the recess andcentered with respect thereto.

Itfwill be noted that the conical surface 24 at its point of Contactwith the curved portion be provided with conical ends of various sizes.

l such devices to close the ends oi the tubular stock.

The lower platen I2 has a cylindrical hole 2l extending inwardly from abottom edge 30 and a cylindrical aperture 32 on the upper side smallerthan the ho1e'28 and communicating therewith. Within the hole 28 is aninsert 34 forming a part of the lower platen. with its lower surfaceflush with the surface 30 of the platen and an upper edge abutting ashoulder 35. The insert has a recess comprising a cylindrical portion 88having a Idiameter substantially equal to the outer diameter of the tubestock I4 and an annular inwardly curved recess portion 40 similar to therecess portion I8 of the upper platen..

Likewisethere is provided a plug 42 having an upper conical portion 44extending centerably within the recess with the conical surface 48 atits point of contact with the curved portion 40 at substantially a rightangle. The recess 48 is supplied for receiving the plug 42.v

lIn the aperture 82 of the platen l2 a sleeve 58 is inserted until itabuts 4an upper annular rim 54 of the insert 34. The sleeve is designedto fit snugly within the aperture buthas an inner diameter 56substantially greater than the outside diameter of the tube stock I4.Opposed centering devices comprising spring members 58 are secured tothe sleeve by means of screws, TheseA spring members are normallyarcuate in shape as shown in Figure 3, and of resilient material such asspring steel. These are secured to the sleeve in horizontal position.

At each end of each of the spring members there is provided a hole orslot within which is positioned a pin 62. The pin extends through a hole64 in the sleeve within which it has a free sliding nt and has a cap 66securing it to the end of the spring member.

In the form of my invention shown, four pins are provided positioned inpairs and opposed to each other. The pins are permitted to movelongitudinally with respect to their axes and are normallyspring pressedinto the position shown in Figure 3 by the spring members 58.-

In Figure 4 there is shown a body18 of relatively cool liquid su'ch aswater held in a container 12 and having a depth slightly less than thelength of the tubular stock I4 permitting an end 14 to extend above thesurface of the water. The length of the end 14 is substantially equal tothe portion of the tube which is to be formed into a rounded closed end16 as seen in Figure 2. In theparticular embodiment shown in Figure 4.there is provided a torch 18 designed to impel a heat stream 80 againstthe exposed portion of the tubular stock. It is contemplated, however,

and within the scope of my invention to provide a shallow bath of liquidsuch as lead lheated to the temperature necessary for annealing thetubular stock in order that the stock might be dipped in it. to thedepth desired for forming A the closed end 16.

.edges-properly squared. Next, using one` of the 'forms of my method thestock is placed in a bath of relatively cool liquid to a depth such thatthe end protruding above the surface of the liquid is no longer than thelength of the tubing stock desired to be heated and annealed.

The protruding end lcan then be readily heated by a torch as shown inFigure 4 or by some suitable similar means to a temperature preferablyAends of the tube `are to be closed, the stock is inverted in the liquidbath and the opposite end heated and doused.

After this has been done the stock is placed in the cylindrical portion38 of the recess in the lower platen as shown in Figure 1 by slipping itdownwardly through the sleeve 58. When in this position the lowercylindrical portion 38 holds the bottom endl and the pins 62 bearingagainst the side walls of the stock centered properly `with respect tothe recess and the conical end 44 of the-plug 42. Next, the upper platenis lowered by suitable power machinery to the position shown in Figure1, wherein the cylindrical portion 20 of the recess surrounds the upperannealed end of the tubular stock.

Then the platens I0 andl I2 are forced together by power means and whilebeing so forced together, the tubular stock is forced into the form I6,shown in Figure 2, while remaining in a carefully adjusted centerposition by the centering pins. During the compressing stroke the endsof the stock which have been annealed are formed over into the curvedends 16 lying flat against the annular curved portions I8 and 40,respectively, of the recesses. The end edges of the stock are driveninwardly into the recesses until they make edgewise contact with theconical surfaces 24 and 46 of the respective plugs 22 and 42.

When this operation has been completed, the

' platens can be readily separated one from anready for the nextcontainer forming operation.

In the meantime, the container i6 thus shaped may be further machined byreaming the ends formed bythe plugs to size in preparation Afor theinsertion of a standard fitting.

There has thus been provided a .method and' apparatus for making` asingle piece'of tubular Istock into a high-duty closed. containervwhich` when equipped with the necessary fittings is suitable for use inhigh-pressure gas and. liquid lines withoutdanger-ofleaks and with arelatively minimum necessity for adjustment and repair. Some changes maybe made in the construction and arrangement of th'e parts of my deviceWithout departing from the real spirit and purpose of my invention, anditis my intention to cover by my claims any modified forms ofstructure,v or use of" mechanical equivalents, which may be reasonablyincluded within their scope. v

I claim as my invention:

l. A device for forming a cylindrical length of tubing stock into achamber having rounded, relatively closed ends comprising a platenhaving an aperture therein including a cylindrical portion for receivingsaid stock, an inwardly curved annular wall forming av bottom for saidaperture and a centering element extending intothe recess at the centerof said bottom, a second platen having an annular curved recess thereincomplementary to said first recess having a-limlited reciprocal movementrelative to the first' ing devices in the sleeve, leach comprising a vspring pressed, laterallyreciprocable element secured to the sleeveextending through the sleeve wall 'to a point of contact with the wallof said stock and releasably held in said positions.

2. A device for forming a cylindrical length of tubing stock into achamber having rounded, relatively closed ends comprising a platenhaving an aperture therein including a cylindrical portion greater indiameter than said stock, a

shoulderbeneath said cylindrical portion and an inwardly curved annularwall forming a bottom for said aperture, a plug extending into therecess at the center of said bottom, a second platen having an annularcurved recess therein complementary to said ilrst recess having alimited reciprocal movement relative to the first platen to and from a'compressed position, a central plug in said second recess, a sleevefitting within the aperture oi' the ilrst platen positioned against saidshoulder and extending outwardly beyond the surface to a position spacedfrom the compressed position of said other platen, and a plurality ofopposed centering devices'in th'e sleeve,

each comprising a spring pressed laterally recipmcable element securedto the sleeve extending through the sleeve wall to a point ofcontactwith the vwall of said stock and releasably heldin said positions forcentering the tube stock relative to theplugs.

3. A device for forming a cylindrical length of tubing stock into achamber having rounded, re1- atlvely closed ends comprising a platenhaving an aperture th'erein including a cylindrical portion greater-indiameter than said stock, a shoulder beneath said cylindrical portionand an inwardly curved annular wall forming the bottom -for saidaperture, a second platen having an annular curved recess ythereincomplementary -to said first recess having a limited reciprocal movementrelative to the first platen to and from a compressed position, a sleeveilttlng within the aperture of the nrst platen positioned against saidshoulder and extending outwardly beyond the surface to a position spacedfrom the compressed position of said other platen, and opposed tcentering devices in the sleeve, each comprising an arcuate springelement surrounding a portion of th'e circumference of the sleeve intransverse position, a screw securing the center of said element to thesleeve and reciprocably mounted pins secured sleeve wall to points ofcontact with the wail of said stock and releasably held in saidpositions by said spring element.

ture therein greater in diameter than said stock and a base therefor, acylindrical hollow inner member within the aperture, said inner memberhaving a recessincluding a cylindrical side wall portion having a depthsubstantially/equal to the length of said stock adapted to be formedinto one of said closed ends and equalin diamel .ter to the diameter ofsaid stock, a shoulder at i ing one at each end of each said elementextending through the 4. A device for forming a cynnd'ricn lengthy oftubing stock into a chamber having rounded, relatively closed endscomprising a platen having an outer member including a cylindricalaperthe top of said recess beneath said aperture and an inwardly curvedannular wall forming the bottom of said recess and a plug extending intothe recess at the center of said bottom, a second platen having anannular curved recess therein complementary to said first recess andhaving a limited reciprocal movement relative to the iirst platen to andfrom a compressed position, a central. plug at the bottom of said secondrecess, and a sleeve iittlng within the aperture of the rst platenpositioned against said shoulder and extending outwardly beyond thesurface to a position spaced from the compressed position of said otherplaten, and opposed transverse centering devices in the sleeve, eachvcomprising an arcuate spring element surrounding a portion of thecircumference of the sleeve in transverse position, a screw securing thecenter of said element to the sleeve and reciprocably mounted pinssecured one at each end of each said element extending through thesleeve wail to points of contact with the wall of said stock andreleasably heldin said positions by said spring element.

5. A device for forming a relatively long cylindrical length of' tubingstock into a chamber having the mid portion thereof possessed of thesame cylindrical shape as said tubular'stock and having rounded,relatively closed ends comprising, a platen having an aperture thereinincluda short cylindrical section having the same internal diameterasthe external diameter 'of said stock adapted to iit around the end ofsaid stock, an inwardly curved annular wall forming a bottom for saidaperture, a second platen having an annular curved recess thereincomplementary to said rst recess including a short cylindrical sectionhaving the saine diameter as the external diameter of said stock aroundthe other end of said tubular stock, said platens having an initial openposition for insertion of the tubular stock, and having a limitedrelative reciprocating movement to and from compressed positions, aninitial compressed position wherein each end. of the tubular stock '1Sheld within the respective short ,cyllndrlcal than the initial diameterof the tubular stock.

GEORGE E. FRANCK.

adapted to iit wherein the

